Biology

You are analyzing a compound in the laboratory. You find that it is made up of carbon, hydrogen, and oxygen in a ratio of two hydrogen atoms for each carbon atom. How will you classify the compound? A. lipid B. protein C. carbohydrate D. nucleic acid

C. carbohydrate Carbohydrates are made up of Carbon, hydrogen, and oxygen. See the video for the basic carbohydrate structure.

The human body maintains a temperature of around 98.6 degrees at all times. Enzymes are involved in almost every chemical reaction in the body. Which of the following describes the connection between these two statements? A. Enzymes function best at a specific temperature. B. The body needs to be warm to prevent hypothermia. C. The body is kept relatively warm to prevent too much enzyme action. D. There is no connection between the two statements.

A. Enzymes function best at a specific temperature. Enzyme activity is affected by temperature. Each enzyme has a specific temperature range in which it works most effectively. Most biological enzymes present in the human body have an ideal temperature range of around 98.6 degrees.

As food travels through the digestive system, it is exposed to a variety of pH levels. The stomach has a pH of 2 due to the presence of hydrochloride acid (HCl), and the small intestine has a pH ranging from 7 to 9. HCl converts pepsinogen into pepsin, an enzyme that digests proteins in the stomach. Which of the following most likely happens to pepsin as it enters the small intestine? A. It becomes inactive. B. It begins to replicate. C. It's shape changes to engulf large proteins. D. It's activity increases to digest more proteins.

A. It becomes inactive. Enzymes have an ideal pH, at which they best function. Many enzymes cannot function at all outside their ideal pH range. Pepsin functions best in the extreme acid environment of the stomach and will, therefore cease to function in the much higher pH of the small intestine.

The enzyme lactase will break down the sugar lactose into which of the following components? A. monosaccharides B. nucleic acids C. amino acids D. phospholipids

A. monosaccharides Sugars are made of building blocks called monosaccharides.

Fats, oils and cholesterol are all types of what? A. cell membranes B. hormones C. lipids D. fatty acids

C. lipids See the structure of lipids in the video.

RNA and DNA are which type of macromolecules? A. carbohydrate B. lipid C. nucleic acid D. protein

C. nucleic acids DNA is deoxyribonucleic acid and RNA is ribonucleic acid.